/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.util;

import java.util.Collection;
import java.util.HashSet;

/**
 * Extended implementation of <strong>HashSet</strong> that includes a
 * <code>locked</code> property. This class can be used to safely expose
 * resource path sets to user classes without having to clone them in order to
 * avoid modifications. When first created, a <code>ResourceMap</code> is not
 * locked.
 * 
 * @author Craig R. McClanahan
 * @version $Id: ResourceSet.java 939353 2010-04-29 15:50:43Z kkolinko $
 */

public final class ResourceSet extends HashSet {

	// ----------------------------------------------------------- Constructors

	/**
	 * Construct a new, empty set with the default initial capacity and load
	 * factor.
	 */
	public ResourceSet() {

		super();

	}

	/**
	 * Construct a new, empty set with the specified initial capacity and
	 * default load factor.
	 * 
	 * @param initialCapacity
	 *            The initial capacity of this set
	 */
	public ResourceSet(int initialCapacity) {

		super(initialCapacity);

	}

	/**
	 * Construct a new, empty set with the specified initial capacity and load
	 * factor.
	 * 
	 * @param initialCapacity
	 *            The initial capacity of this set
	 * @param loadFactor
	 *            The load factor of this set
	 */
	public ResourceSet(int initialCapacity, float loadFactor) {

		super(initialCapacity, loadFactor);

	}

	/**
	 * Construct a new set with the same contents as the existing collection.
	 * 
	 * @param coll
	 *            The collection whose contents we should copy
	 */
	public ResourceSet(Collection coll) {

		super(coll);

	}

	// ------------------------------------------------------------- Properties

	/**
	 * The current lock state of this parameter map.
	 */
	private boolean locked = false;

	/**
	 * Return the locked state of this parameter map.
	 */
	public boolean isLocked() {

		return (this.locked);

	}

	/**
	 * Set the locked state of this parameter map.
	 * 
	 * @param locked
	 *            The new locked state
	 */
	public void setLocked(boolean locked) {

		this.locked = locked;

	}

	/**
	 * The string manager for this package.
	 */
	private static final StringManager sm = StringManager
			.getManager("org.apache.catalina.util");

	// --------------------------------------------------------- Public Methods

	/**
	 * Add the specified element to this set if it is not already present.
	 * Return <code>true</code> if the element was added.
	 * 
	 * @param o
	 *            The object to be added
	 * 
	 * @exception IllegalStateException
	 *                if this ResourceSet is locked
	 */
	public boolean add(Object o) {

		if (locked)
			throw new IllegalStateException(sm.getString("resourceSet.locked"));
		return (super.add(o));

	}

	/**
	 * Remove all of the elements from this set.
	 * 
	 * @exception IllegalStateException
	 *                if this ResourceSet is locked
	 */
	public void clear() {

		if (locked)
			throw new IllegalStateException(sm.getString("resourceSet.locked"));
		super.clear();

	}

	/**
	 * Remove the given element from this set if it is present. Return
	 * <code>true</code> if the element was removed.
	 * 
	 * @param o
	 *            The object to be removed
	 * 
	 * @exception IllegalStateException
	 *                if this ResourceSet is locked
	 */
	public boolean remove(Object o) {

		if (locked)
			throw new IllegalStateException(sm.getString("resourceSet.locked"));
		return (super.remove(o));

	}

}
